Broken Arrow City Council
Meeting of: 04-17-2018
To: Mayor and City Council Members
From: Development Services Department
Title:
title
Presentation and update related to the Land Subdivision Code, Article VI, Miscellaneous Requirements, Policies and Approvals, Section 6.2 Miscellaneous Requirements; more particular sanitary sewer backwater device (backflow preventer) for buildings in Broken Arrow
End
Background:
Council reviewed Ordinance 3523 at the April 3, 2018 Council meeting. The portion of the ordinance pertaining to Section 6.2 involving sanitary sewer backflow prevention for residential and commercial lots stated:
“The modification to Section 6.2, miscellaneous requirements, adds an additional requirement for finished floor elevations. This item states that finished floor elevations shall be placed on the face of the plat. If the lots are connected to a sanitary sewer system, then a backflow prevention table is required on the face of the plat.”
Council asked if the ordinance required all lots to have backflow preventers on the sanitary sewer service lines. Staff stated that they believed City ordinance only required a backflow preventer on lots with a finish floor less than the one foot of the upstream manhole rim of the sanitary sewer. Council thought the ordinance had changed recently requiring all lots to have these devices. Staff indicated that they would research City ordinance and report back for clarification.
From Council’s direction, we found that in 1977 the City Council passed an ordinance creating Section 24-303 requiring, “In all instances in which the lowest floor of a building which is served by a sanitary sewer is less than one foot in elevation above the upstream manhole rim of the same sanitary sewer, the owner of the building shall install a backwater device near the building, in a meter can, or in any other enclosure approved by the city, with all working parts readily accessible for service and repairs. Installation of these devices and all maintenance thereon shall be at the expense of the property owner.”
Then in 1998 there was an attempt to add an additional line to the code by Ordinance No. 2173, “In all instances in which the lowest floor of a building which is served by a sanitary sewer is less than one foot in elevation above the upstream manhole rim of the sanitary sewer which serves that property, or where there has been a previous overflow into the building, the owner of the building shall install a backwater device near the building, in a meter can, or in any other enclosure approved by the city, with all working parts readily accessible for service and repairs. Installation of these devices and all maintenance thereon shall be at the expense of the property owner.” It was found that Ordinance No. 2173 was noted to attempt to change Section 24-100, not Section 24-303.
In 1999 the City Council passed Ordinance No. 2224 updating all of Chapter 24 and this did change Section 24-303 to: “In all instances in which the lowest floor of a building which is served by a sanitary sewer is less than one foot in elevation above the upstream manhole rim of the same sanitary sewer, the owner of the building shall install a backwater device near the building, in a meter can, or in any other enclosure approved by the city, with all working parts readily accessible for service and repairs. Installation of these devices and all maintenance thereon shall be at the expense of the property owner.” This ordinance may have changed the ordinance removing, “the sanitary sewer which serves that property, or where there has been a previous overflow into the building”.
Also, staff looked at both the International Building and Plumbing Code and the International Residential code and found that both closely matched City ordinance.
2015 International Plumbing Code: 715.1 Sewage backflow. Where plumbing fixtures are installed on a floor with a finished floor elevation below the elevation of the manhole cover of the next upstream manhole in the public sewer, such fixtures shall be protected by a backwater valve installed in the building drain, or horizontal branch serving such fixtures. Plumbing fixtures installed on a floor with a finished floor elevation above the elevation of the manhole cover of the next upstream manhole in the public sewer shall not discharge through a backwater valve.
Exception: In existing buildings, fixtures above the elevation of the manhole cover of the next upstream manhole in the public sewer shall not be prohibited from discharging through a backwater valve.
2015 International Residential Code: P3008.1 Sewage backflow. Where the flood level rims of plumbing fixtures are below the elevation of the manhole cover of the next upstream manhole in the public sewer, the fixtures shall be protected by a backwater valve installed in the building drain, branch of the building drain or horizontal branch serving such fixtures. Plumbing fixtures having flood level rims above the elevation of the manhole cover of the next upstream manhole in the public sewer shall not discharge through a backwater valve.
Exception: In existing buildings, fixtures above the elevation of the manhole cover of the next upstream manhole in the public sewer shall not be prohibited from discharging through a backwater valve.
City staff recommends no changes to the current City ordinance but if Council desires that all buildings have a backflow preventer on the sanitary sewer service line, Staff will amend the ordinance accordingly.
Cost: None
Prepared By: Michael Skates, P.E., CFM, Development Services Director
Reviewed By: Utility Department
Engineering Department
Legal Department
Assistant City Manager, Operations
Approved By: Michael L. Spurgeon, City Manager
Attachments: None
Recommendation:
At City Council direction